Sahih Muslim , Book 4, Hadith 1877 (USC-MSA) ⓘ
Jabir b. Abdullah reported that the Apostle was delivering the sermon on Friday in a standing posture when a caravan from Syria arrived. The people flocked towards it till no one was left (with the Holy Prophet) but twelve persons, and it was on this occasion that this verse in regard to Jumu'a was revealed." And when they see merchandise or sport. they break away to it and leave thee standing."
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، وَإِسْحَاقُ بْنُ إِبْرَاهِيمَ، كِلاَهُمَا عَنْ جَرِيرٍ، - قَالَ عُثْمَانُ حَدَّثَنَا جَرِيرٌ، - عَنْ حُصَيْنِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ سَالِمِ بْنِ أَبِي الْجَعْدِ، عَنْ جَابِرِ، بْنِ عَبْدِ اللَّهِ أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَخْطُبُ قَائِمًا يَوْمَ الْجُمُعَةِ فَجَاءَتْ عِيرٌ مِنَ الشَّامِ فَانْفَتَلَ النَّاسُ إِلَيْهَا حَتَّى لَمْ يَبْقَ إِلاَّ اثْنَا عَشَرَ رَجُلاً فَأُنْزِلَتْ هَذِهِ الآيَةُ الَّتِي فِي الْجُمُعَةِ { وَإِذَا رَأَوْا تِجَارَةً أَوْ لَهْوًا انْفَضُّوا إِلَيْهَا وَتَرَكُوكَ قَائِمًا}
also referenced under: Book 7, Hadith 47 (In-Book) & Hadith 863 (Reference)